When building tk in the cygwin environment, the Makefile dependencies should use the cygwin file names not the Windows native ones. Currently, the following error message is given:
Makefile:419: *** target pattern contains no `%'. Stop.
And if that one is fixed, there's an other one on line 425 (the line numbers are from tk 8.5b3).
Attached is a patch that changes the two dependencies on
TCL_SRC_DIR_NATIVE to TCL_SRC_DIR in tk-src/win/Makefile.in.
patch for tk-src/win/Makefile.in